Feed drive means for machining concave and convex surfaces



Sept. 14, 1943. E. P. BU 1130 2,329,246

FEED DRIVE MEANS FOR MACHIQNY oucmzs AND 'CONVEX SURFACES Filed M'ch so, 1939 s Sheets-Sheet 1 'INVENTOR Enwmw FIB ULLHRD, .ZZT

' ATTbRNEf c Sept 1943- E. P. BULLARD, an

FEED DRIVE MEANS FOR MACHINING CONCAVE AND CONVEX SURFACES Filed March 30, 1939 3 Sheets-Sheet 2 Z 52, INVENTOR ll/I/l/Il/l/ li Ill/Ill Sept. 14, 1943. E, P. BULLARD, so

FEED DRIVE MEANS FOR MACHINING CONCAVE AND GONVEX SURFACES 3 Sheets-Sheet 3 Filed March so, 1939 JNVENTOR 'Enwnnn RBl/LLARDJZZ' ATTORNEY Patented Sept. 14, 1943 Connecticut v e 7 Application marchco, 1939, Scrial'No. 26459;? f

' 18 Claims. o1.s2" "-1'9)' This invention relates to ,a means n for ma: chining irregular surfaces of revolution and more particularlyito a me'ansio'r moving a cutting tool over a rotating workpiece having either a concave or convex surface.

The'feed drive means of the present invention is intended for, and illustrated as -a mechanism particularly adapted to rnac'hineftools in which a tool element is under the optional control of two driving means emerging from a single source. This invention is applicable, in "general; to machine tools in which .atool element maybe moved in two lines ofdirectionat an angle'of '90 degrees withrespect to; each other. 7 V

The general object of the invention is to pro.- vide a feed drive means'simple and efficient and with a wide range of usefulness and with a minimum of interference withthe 'norrnaloperation of the machine. 1 a

Another object is to provide an improved con tinuous drive which will permit a tool element, mounted for motion in any direction, to iollow'a cam throughout an arc of 90 degrees;

- It is another object toprovide means to ima required, depending upon the direction in which I the tool element moves.

It is an objectto'connectrtwo sources of, tool drive by a mechanism commonlyknown as a difierentialwhich partakes of certain advantages to permit a varying degree of effectiveness :of

the two sources;

' Itris a particular object the invention to control the movement of :the tool elementby a cam in conjunctionwithia differential effecting in'a I certain elementsof the mechanism may bare'aw.

ily'moved so as not to interfere with v the normal operation of the machines v Another object is to provide means' to"return.

the removed elements and a'cc'urately lock them in their'former relationship, permitting operation 7 means,

to be resumed that requires' the' differential I mechanism. 1

A still further object is to provide 'a' selective control whereby a machine tool may be either operated in anormal manner orwith the differ ential mechanism. 1 I I With the foregoing and other objects, m-view;

the invention consists offa novel differential-con: nection between two drive means forimparting movementto a mi element; said movement be: ing under the control of acam conforming to a desiredcontounf In the drawings; v Figural represents a front view of. avertical machine toolto which the 'inventionis applied, onlythe essential parts being shown. Figure 2 represents an enlarged iew, partly'in 7 section, of the mechanism on the right hand end of the cross rail.

Figure3represents anenlarged side view .oi'a I portion of the machine tool, partly in section, taken jon the line 3-3 of Figure l.

., Figure 4 represents a section taken ontheline 7 4-4 of Figure 3.

Figure 5 represents an enlarged-top plan view of aportion of the cross rail and headto which the invention is applied. i l

Figure I 6 represents a fragmentary section taken on the'li'nefi efi of Figure 5;, I

Figure 7 represents a riragmentaryascction taken ,on the line of Figure .5'; and.

Figure 8 discloses, partly in section, an 1llustrative work piece of another form having a concave surface which maybe tooled one machine equipped with the improvedfeed drive means.

Referring to tha drawings, the invention is depicted as applied to -a verticalturret lathe of the-type shown and described in the 'Bullard PatentsNos, 683,592, 1,690,568 and'1,'l49,37; 'It is to be understood ;the5invention is not limited to the type of machine shown'butj is applicable to any machinetool'in which the movement of thetool head is effected'by a feed rod and afed screw the movement produced by one being nor mally at right angles'to the movement'produced byitheother.

Referring more particularly to Figure the lathe comprises a base In provided-with a'hori zontal' chuck table I l rotatable about" a vertical axis. Driving means,'both for the table and tool feed, amay be provided from a pulley [2 or other A standard? H] rising inwardly from the hase 10 is adapted" to support vertical slideways l3 .and I4 upon which is mounted a crossrail 15;:

means being providedfsuch as bolts it and I1 (Figure 5), for clamping the crossrailin position to accommodate work of varying heightj'secured .to thetable II. if I'he rossran is provided with suitable horizontal ways" l8 and 19 upon which a saddle 20 is slidably mounted, A swivel 2!, bolted to the saddle 2D; is provided with slideways 22 (Figure'5) to 'receivea turret"slide"23 upon v which is mounted a tool holding turret 24. I This turret carries a holder 25 in which may be se cured a tool 26 adapted to the needs of a work piece 21. The mechanism for imparting horizontal movement to the saddle 20, turret slide 23 and turret 24 includes a feed screw 28 journaled in one end of the crossrail l and engaging a hollow threaded nut "z iFigures 5 and. 7),-se-' cured to said saddle 20. The arrangement being such that rotation of the feed screw within the nut will effect longitudinal movement to the- 7 saddle. A feed shaft 30 is likewise journaled-in the end portion of the crossrai'l l 5 anda worm The shaft 45, on which the clutch gear 45 is journaled 'i s supported within housing 43b by a'bearing in a partition 430 of said housing.

32 is keyed thereto for rotation therewith. The

worm 32, through a worm gear nga shaft-34 l and a pinion 35, engages a rack 36 toi'mpart vertical motion to the turret slide 23.

Handwheels 31 and 38 are providedupon the ends of ,the feed screw 28 and feed shaft 30 r spectively by which an operator can bring the tool to itsfinal adjustment with respect to the work piece. w

A worm 39 is secured to one end of allslmaft (Figure 4) upon the other end of which is Se cured a bevel gear 4|. A shaft .42Qparallel to the feed shaft 30 and thefeed. screw 28jand positioned midway between them, is journaled in a casing 43 which is secured to .theback of the crossrail l5. The casing 43 contains areversible feed. driving means, not shown, forjthe shaft '42. Since the invention is not concerned with the driving means of the shaft 42,:it will sufilce'to say the shaft may beidriven from the main driv ing pulley, either forward or in lli yerse andlat different speeds by a conventional speed change gearing to permit a variation in the cutting feed of the. tool. Keyed to the shaft .42'is. a double gear 44. One element of the gear 44 constitutes a primary driving meansfforthe screw28f'and the shaft 3U, and drives the wormv 39 through the bevel gear 4| keyedtotheshaft '40. The other element of gear 44 drives a clutch bevel gear 45 running'free on'a shaft'ldwhichgeetr 45 constitutes a portion of a secondary driving means for screw"28 and shaft 38. The shaft is journaled in-an arm 41-adapted' to swing about thesha-ft fl and normally positioned to hold the worm 39' in adisengaged neutral position between two worm 'ge'ars 48 and-49, secured upon the feed screw 28-and the feed shaft 3!) respectively f'I'he worm}! is adapted to'beswung up, or down, to mesh with eitherof the' be'fore-men' tioned worm gears and 49. .It is obvious the -worm' 39' can engage'o'nly one of the-worm gears and 49 at a time. Thus. when the worm. 35

engages the worm gearH4B, thetool head? 24 ings in the swivel 2|, and. to followthe contour prescribed by acam havingthe-desiredform.

The invention includes a connection between the feed screw 28 and-the feed shaft 30'comp 'ising a differential (see Figure/2),

- It will be understood the worm 39 is in a neutral position, with respect to the=worm gears 48 and 49, during the operation of the differential.

The clutch bevel gear is provided with a "clutchface forengagement by a clutch sleeve 50 sp'lined upon the shaft 46 and adapted to be shifted into'engagement by a lever 5|. When it is desiredtooperate the differentiahthe lever 5| 5 is moved to engage the clutch sleeve 50 with the clutchon the bevel gear 45. Rotation of the shaft=42 will now rotate the shaft 46 and apin- 5B,,that extends through the housing 54and a I ion.,52.keyed; thereto (Figure 3). The pinion 52 m'eshes'with, a bevel gear 53 surrounding and securedto a differential housing .54. The housing 54 contains the usual arrangement ofgears. .A

gear 55 (Figure 2). is keyed'to'anuprising shaft wall of housing 431) and a similar gear 51 is keyed to a shaft 58 that extends downwardly through the housing 54 and another wall of housing 43b. The/gears 55 and 57' areadapted to mesh with both bevel gears SSand fifl running free on their respective .stubshafts 5! and 62 positioned at right angles'to the shafts 56 and 58. Upon the upper end of the shaft'56 isxsecured a I bevel gear 63, meshing with a companion gear 64 keyed-to the feed shaft-30. Likewise upon'the lower end. of the shaft 58- is secured a bevel gear 65 meshing'with clutch gears '66 and 66A freely mounted upon the feed screw 28. The clutch gears and MM are engageable with a shi'ftable clutch element BBB splined upon the feed screw 28, wherebythe direction 'of rotation of the feed' sc'rew may be changed byengaging the clutch element with either one ofthe clutch gearsfifi or 66A. A suitable controllevermay be utilized for shifting'th'is clutch element manually. ThusQit Wi11 b6 seen therotation ofthe housing54 will rotate both the feed shaft 30 and the feed screw"; but owing to the differential arrangement, .the feed shaft 30 and the feed screw28 "may rotate at'difierentspeeds, or one may remain'idlefwhlle the other is driven by the housing 54. To control the amount oftool feed tobe imparted to the tool bythe' feed screw 28,-or the feed-shaft 30, orthe rcom'bined feed of'b'othythe inventiomincludes*awcam path 61 (Fig. 1) conforming tothe contourof-the finished workpiece, ."Ifhe cam pat-hG'I engages a roller- :68 Tomm mounted on a stud :69 rigidly secured to the turret slide 23 (Fig. 7). Thedcam path is formed in a block Hia-djustable ina'pair of slideways H and 12 formed in aicam'carrier 1-3. By rotatinga-screw -'I4:(Flg 1),-th,e block 10 maygbeadjusted horizontally and "when properly positioned may be secured lay/a binder clamp 15 secured by screws". The cam carrier 1'3 is slidably mounted in dovetailed ways in a sup- .port 11, said support embracingthe upper-slide way I8 (Figure'fi) of the cross rail l5 and secured to the lower slide way-l9 by -bo1ts18;. A rack I9 (Fig. .1), secured to the lower face .015 the camcarrier 13, engages "a pinion-,secumdto be noted the cam path 61 is-open-at the'upper and lower ends-allowing theroller 68 'to be moved ence with any subsequent movement of thetu'r .ret slide 23. When it is desiredto" reinstate the roller 68 in the cam path, 61,- the'cam carrier 13 ismoved by rotation of the crank 82 to-position the opening of the cam path inalignmentwith the roller and by operation of-the feed *screw 28 and feed shaft 30, the 'roller is again located in thedesired positionin the path. In order thatthe roller may be returned to the precise position, in the cam path, after having been removed therefrom, a lockpin arrangement 85 is provided in the camcarrier'IS'engaging-a bore 86in the support 11. Thus ,the'cam earrierf|3 may be locked in fi xed 'position with respect-to the support Tl.

The cam carrier maybe rigidly mountedin the Q ways 83 and 84, by a taper gib 8'17 (Figures?) and 6) positioned between the way 83 and the abutting surface of the support'l'l. j'

If. it is desired to-rnove the'cam c a 'rrierfflS the taper gib 87 must'first be loosened by a lever and screwarrangementlocated on the end of the cam carrier.

acting upon a screw 90, secured to'the end of the gib 81, will tend to'pull the taper gibout sufficient to. allow easy movement of the joarn the contour of a finished piece, is securedin .the v.

table 1 Ill. It will benoted that the contour varies 'fromthe horizontal down an incline .to

the vertical, ,or through an arc of--90 degrees. The usual operation of the tool head is through A partial rotation of a :lever' 88, (Fig. 5) rotatably mounted ina bracket '89,

clear of the cam block 10." While the roller'68'is carnpam facilitating t e -r=emoval an replacelOr mentor the work piece 21 y 1 igur l discloses a-work pieCe with the tool operating to; machine a convex surface. It is 'de'sira'blein s'ome lnstancesito'machine a concave vsurfacesuch as the inte'rnal 's'urface of a work p ece 21A illustrated in 'Figure s, It being I only necessa y; to substitute for the earn "plate 10 '(Figure 'l) a cam plateprovi'ded with-a groove corr sponding 1 to the finished work piece; "In thisexamplethe feed shaft 30 wouldb'e rotated to'inove 'a tool 26A downwardandfthe feed screw 28=w6iild be rotated tofm'ove the tool to the left to theicenter of rotation of the work-piece. Thus thefcomp'ounded'motions of the feed shaftfand feed screw-under control" of] a camgroove would causethe tooltoprqduc'the desired concave surface onthe work piece." Cam plates may be provided inwhich the cam groove may {assume-various forms forjdifferentcontours of work pieces. The 'gi oove ma'y curve from the horizontal downwere to the right or left or curve 'fiomthe horizohtalllbward to the right'or left. The tool 2.

. ay be caused to move horizontally either right gov ' the forming attachment-the clutch 50 is dis'em the worm 39 meshing with either one of the worm f,

gears 48 or 49. When contour, cutting is desired,

the worm'39 is kept in neutral, asillustrated." The clutch element 66B onthe feed'screw 28 will be in position to effect movement ofv head would be at the beginning of the cut. Moving the lever'El to engage the clutchelement 50 7 with the rotating clutch. gear 45' onjthe shaft 4? willrotate the gear 53'and the differential hous ing 54 causing rotative force'to be imparted to the gears 64 and '53 tending, inthis example, to?

rotate the feed shaft 3il to feed the tool down aridthe feed screw 28 to feed the tool to the right. The roller 68, laying in a horizontalplane in the'cam path, precludes the down feed of ,thetool, preventing the feed shaftfillfrorn revolving, the differential action of the mechanism allows the feed screw 28 to revolve, feeding the I tool to the right. Continued rotation of'the feed screw will move the roller tothe curved and inclined portion of the cam pathfallowingi both L .the feed screw and the'feedshaft ,to become operative until the roller reaches the perpendicular portion of the campathi The feed screw has now become inoperative,

the tool feeding dowrnfrom the action of the feed shaft 33 alone, to the end "of-the-cam path I or left} depending uponthe. engagement: of-v the cl'utc'lfi;element GBB on th e reed screw 8 with eitherthe clutch gearfl fiii 01*65A, also the feed shafttllinay berotated to caiise the tool to move either upward or "downward depending upon the direction ofrotation of the drivingsha'ft;flwhich einsf' the 'rotation -of-"the differential housing Thus the tool maybe guided through any 'greeangle i 'f' 3 Wlien it is desired to use this machine without gaged from I the clut'ch gear 45, and the clutch element lififi is retained in"a neutral position. h W 3915 a ed w th the mi ea ia. 'or l ,9 ovejh roll fiil, out ofthe cam path. rnelockpin' s5 iswithdrawn froin the bore 186 thei support 11] and the leverf-88 "is rotatedto lo s n th lflfili T nice t "b mo ed' v h. kitt t e r ii' the-crankjz sio as to befout-eftheway ofthefroll EB'on'the slide 23. From the foregoing,'it*vvill be seen that the mechanism provides a' simple, efficient'and effectual mechanism for properly carrying out the objects of the invention. It will be understood the amoaratus may assume various modifications and changes and the full-use of equivalents may be resorte'd'to Without departing fr'orn the spirit and scope of the invention as outlined in; the appended-claims. 3 a Having'thusdescribed myinvention, what I claim and desire to secure by Lette rs Patent is:

V I 1. Ina metal working machine tool for ma chiningirregular' surfaces of revolution, a tool holding element; a cam forcontrolling the move ment' of said tool-holding element; .a feed" screw adapted to impart a rectilinear movement to said; element; a feed shaft adapted to impart a rectilinear movement transversely toithe firs't moveincluding a idifierential gear unit adapted to. allow said feed shaft and/or said-teed screw to operate :at different relative speeds, whereby to impart 'movementto sa-idtool holding element independently or collectively under the control .of saidcame 2.'In -a mach" surfaces of revolution, a-toolholding;element; a slide for supporting said tool holding element; a saddle for supporting said slide tor movement therein; across rail for carrying-said saddle for horizontal movement thereon; a feed shaft for imparting movement to. said, slide-along said saddle; a feed screw for; imparting horizontal movementto said saddle; a'carn roll secured aid slide adapt dt ,en e sa am hn'a plate stationary with respect to saidv cross rail; common means fordriving said screw shaft; and. inter-connected driving means between said shaft and screw, independentof the drive between said screw and shaft and said; common means,- but driven by said common means including a differential gear unit permittin Sa d feed shaft and said feed screw to impart movements to aid slide and sadd e, said movements being govrn db sa dca p t 1 g c c- I l 3. In" a machine a for mac nine irregular sulfides of revolutions, a tool holding element; a slide for; supportingsaid tool holding element; a saddle for supporting said slide for movement therein; a cross rail for carrying said saddle for horizontal movement thereom-a feed shaft for imparting ,movementto said slide a feed screw for imparting horizontal movement: to said sadfile; a cam roll secured to said slide adapted to engage acam pathin -a cam plate stationary With respect to said cross rail; a diflerential gear unitincluding a housing; a driving means forimparting rotation to said housing; said;housing being mounted on two endwise opposed-shafts extending thereinto,'each ofsaid oppofi dshafts being provided with gears meshing with bevel gears rotatably mounted on shafts secured in said housing at right angles to said opposed shafts, the outer end of one opposed shaft -being'provided with means tor, driving said feed shaft, the outer end of the other opposed shaft being pro videdwith means for driving said feed screw; said diflerentiaLgear unit permitting said feed shaft and feed screw to impart movementsto said slide and saddle from said first driving means singly or collectively, said movementsbeing 'controlled by said cam;path; V 4.;In-a machine toolfor machining irregular surfaces of revolution, a cross rail; a saddle mounted thereon for horizontal movement; a slide mounted in said saddle for movement along a path intersecting tha'path of movement of said saddle; a cam'roll attached to said slide; a cam plate; a cam path in-said plate adapted to guide the cam roll; a cam plate carrier forsaid camplate; separate feed driving shafts 'for imparting movement to said slide, and saddle; common meansfor drivingsaid shafts; means lie-'- tween said feed driving shafts, independent of thedrive between said shafts and said common means, but .driven by said common. means and including. a differential gear unit adapted to im- Dartmovements to: said slide'an d'saddle gov:

orned by said cani path; and means for adjust titr...

. ina machine toolior machining irregular Surfaces. of revolution, a. cross rail; a saddle ma a-the e n r h ne; memes 111g, said cam plate -vvith'respect toj'said cam e -tool for machining irregular I slide mounted in said saddle tor movement along .a path intersecting the path of movement of said saddle; acam roll attached to, said slide; a cam plate; alcam; pathin, 'saicl plate,v to guide said of movement of said saddle; a cam roll attached to said slide; a cam plate havingthereon a cam path to guide said roll, said-cam path be ing open at both ends to permit said roll to move free from said cam path; a cam plate carrier shiftable on said cross rail; means for moving said cam plate carrier to disengage the cam roll from the cam path; and relocating means to relocate said cam plate carrier in a predetermined position with respect to. said cross rail, whereby upon/the return of "thecam roll into the cam path said apparatus. attains the setting to that before removal of said can roll from said cam path. v I c 7. In a machine of the character described, a Work holder, means for rotating said Work holde er, a' cross rail adjustable with respect to the work holder, a saddle mountedv for horizontal 0 movement upon said cross rail, a slide provided with tool holding means mounted for movement in said saddle, a cam roll secured to said slide,

a movable member mounted to slide horizontally with respect to said cross rail, a cam plate adjustably mounted in said member, havingthereon a cam path in engagement with said cam '1 roll, a feed shaft adapted to impart movement to said tool holding means, a feed screw adapted to impart horizontal movement to said saddle, aninter-connecting drive means between said feedshaft and feed screw operable by a differential gear unit to impart rotation to said feed shaft and feed screw, in'turn to impart movements tosaid tool holding means, said movements being under the control of said cam path, and a reversible drive for said differential gear unitin cludin'g a manually controlled means for engaging and disengaging said drive.

8. In a machine of the character described, a work holder; means for rotating said work holder, a cross rail adjustable with'respectv to said work holder; a saddle mounted for horizontal terconnecting drive means between said feed shaft and feed screw operable by'a differential gear unit to impart rotation to said feed shaft and feed screw in turn to impart movements to said tool holding means, said movements-being under the control of said cam path, and a reversible drive for said differential including a manually controlled means for engaging and holding means associated with said slide to operate with respect to said work holder, a feed screw adapted to impart horizontal movement differential gear unit being adapted to drive to said saddle, a feed shaft'adapted to impart movement to said slide, common means for driving said screw and shaft, an inter-connected driving means between said screw and shaft independent of the drive between said screw and shaft and said common means, but driven by said common means including a differential gear unit for said shaft and screw, means for reversing the rotation of said inter-connected driving means, independentmeans for reversing the 'rotation of said screw, a cam plate secured to said cross rail provided with a cam groove and a cam tool carrier; independent feed drive means for .moving said tool carrier along intersecting paths; and primary means for'driving said feed drive means; a removable attachment including secondary means for driving said feed drive means, said secondary means being driven by said primary meansbut independent of the drive between said primary and said feed drive means, said secondary driving means beingyadapted to drive said feedtdrive means in proportion to'the resistance encountered by said drive means while moving said tool carrier along a predetermined path.

said feed drive means in proportion to the resistance encountered by said feed drive means; i

and .a cam, adapted to guide the tool-holding element along a predetermined path.

13. A lathe comprising in combination, a pair -of carriages adapted to be moved along intersecting paths; a tool support mounted on one of said carriages; a tool mounted in said tool support; separate rotatable means for controlling the movement of each of said carriages along its respective path; a common drive for rotating either of said separate rotatable means; means for guiding said carriages in accordance with a 11. In a metal-working machine for machin ing irregular surfaces of revolution comprising incombination, a tool-holding element; aflfeed drive means for imparting movement to said tool-holding element; an independent feed drive means for imparting movement to said toolholding element transversely to the first movement; and primary means for driving said feed drive means; an attachment comprising second-. ary means including a differential gear unit for driving said feed drive means, said secondary means being driven by said primary means but independent of the drive between said primary said feed drive means while moving said toolholding element along a; predetermined path.

12. In a metal-working machine for mapredetermined pattern; and means independ ent of the drive between said separate rotat-- able means and said common means but operated by said common means and adapted to be connected to both of said rotatable means for selectively rotating said rotatable means at rates necessary to cause said tool to follow said predetermined pattern.

14. A' lathe as claimed in claim 13, in which the independent means comprises a differential gear unit.

15. A lathe as claimed in claim 13, in which the independent means comprises a differential gear unit; and a cam for guiding said tool support along a predetermined path.

16. In a machine tool comprising in combination, a pair of rotatable shafts for moving a tool head along a pair of intersecting paths; a feedworks transmission for driving said shafts in a positive manner; and an attachment adapted to be removably mounted in cooperating position relatively to said feedworks transmission including means driven by said feedworks but separate from the drive between said feedworks and said shafts, said means being adapted to drive said shafts in proportion to the resistance they encounter in moving said tool. head along a predetermined path. v

17. In a machine tool comprising in combina- -tion, a pair of rotatable shafts for moving a tool positive manner; and an attachment adapted chining irregular surfaces of revolution comprising in combination, a tool-holding element; in-

dependent feed-drive means for moving said element along intersecting paths; and primary means for driving said feed drive means; an at to be removably mounted in cooperating position relatively to said feedworks transmission; a

a differential associated with said attachment adapted to be driven by said feedworks transmission but independent of the drive between said feedworks and said shafts; and means for connecting said differential to, and for disconnecting it from said shafts.

18. In a machine tool comprising in combina-- tion separate rotatable shafts for moving a tool head along separate intersecting paths; a feedworks transmission including common means for driving said separate shafts; an attachment for said machine tool adapted to be removably mounted :in cooperating position relatively to said feedworks transmission; a differential unit associated with said attachment and geared to' said shafts, said unit being adapted to be driven by, said common means but independent of the drive between said common means and said shafts; and a reversing mechanism between said unit and one of said shafts. l I

. EDWARD P. BULLARD, III. 

